Antique Edwardian Black Opal Triplet 9ct Gold RingAntique Edwardian Black Opal gemstone ring set in 9ct yellow gold. The ring features a stunning oval black opal gemstone, the stone has flecks of greens, pinks, yellows. Black opals are the rarest of opals, they were discovered in Australia in the late 18th century. The opal is a triplet which indicates the gemstone has three layered a bottom white layer of stone, central layer of black opal and a domed glass layer to magnify and protect the opal.